Nozzle area trim means



y 3, 1966 J. D. CORBETT, JR 3,249,333

NOZZLE AREA TRIM MEANS Filed Jan. 16, 1963 INVENTOR. Jfl/M/ .0. (416557), Je

BY My;

United States Patent The present invention relates to a nozzle area trim means and, more particularly, to a trim means for blanking off the ends of scroll arms in discrete sectors to compensate for varying characteristics of gas generators.

In applications employing tip turbine fans in combination with a scroll, many different types of basic gas generators are used. In a typical application employing a tip turbine fan for lift in a VTOL installation there may he uses for bleed exhaust gases between the gas generator and the lift fan. Such bleed may be used to drive additional fans and/ or accessories.

The instant invention is described particularly in connection with a lift fan where it has found its primary use although it is not limited to such an installation and may be equally usable in cruise fans as will be obvious from the description.

When the installation is used to provide lift or thrust to an aircraft, then for a given combination of engine exhaust gas pressure, temperature and flow there is a particular scroll discharge area that is necessary to obtain maximum lift as a result of extracting the maximum work out of a given amount of exhaust gas. For example, if the nozzle area in the scroll is too large, it is equivalent to operating a very inefficient type of fan with resultant low lift for a given horsepower from the gas generator.

Thus, variations from the correct scroll area create severe eificiency losses. The result is that a given area is desired in the scroll for a particular engine or gas generator. If the engine or gas generator is changed, a different area may be required. From this it follows that some means should be provided to vary the area so that the scroll is usable with a number of powerplants or with a given powerplant under a number of bleed conditions.

Means have been proposed to increase the nozzle area by providing movable and translating blades between the nozzle partitions or blades and these are satisfactory in some environments. However, in selected applications where the closeness of fit of rotating parts does not permit translation of the blades or where the intermediate blades are subjected to hot exhaust gases, such arrangements are not feasible because of space, weight, and complicated structure limitations. Additionally, the blocking of the nozzles results in severe losses where the blocking occurs in the main flow passage of the gasses.

The main object of the present invention is to provide a scroll nozzle area trim means which is used at the ends of the scroll arms to avoid losses and further wherein the trim means is completely contained within the nozzle envelope.

Another object is to provide such a trim means which presents a minimum amount of movable structure in a hot exhaust gas environment with consequent simplified and lightweight structure.

A further object is to provide such a trim means which may be adjusted in a number of ways to take care of varying conditions of installation as well as gas generator characteristics.

Patented ay 3, 1966 Briefly stated, the invention is directed to a tip turbine fan installation which uses a scroll of generally U-shape and having gas inlet means from a remote gas generator so that gas is directed into both arms of the scroll. A tip turbine fan is disposed closely adjacent the scroll, such as in a horizontal plane for vertical lift. The scroll is supplied with nozzle partitions or blades aligned with the tip turbine to direct gases thereto to drive the fan. Nozzle area trim means consisting of cambered vanes are disposed between the nozzle blades of the scroll.

Preferably, the vanes are pivoted on an axis passing through the vanes to rotate and block the area between the nozzle blades. The vanes are located at the ends of the scroll arms and progress in a selected number toward the inlet to block off the end arms of the scroll in discrete sectors.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, it is believed the invention will be better understood from the following description taken in connection with the accompanying drawing in which:

FIG. 1 is a partial sectional view broken away to illustrate a scroll in conjunction with a tip turbine fan adjacent thereto;

FIG. 2 is a partial perspective view illustrating the trim vanes in the scroll nozzle and adjustment means therefor;

FIG. 3 is a partial cross-sectional view showing the location of the trim vanes in relation to the nozzle blades;

FIG. 4 is an enlarged partial cross-sectional view taken on line 44 of FIG. 1;

FIG. 5 is a view of a typical linkage adjustment for adjusting the vanes; and

FIG. 6 is a view of a modified linkage.

Referring firs-t to FIG. 1, there is shown a tip turbine fan installation that is intended to be driven from a remote gas generator not shown. The installation, which may be in the wing of an aircraft, has a scroll generally indicated at 10 and of general U-shape as shown, with gas inlet means 11 preferably in the bight of the U to direct gas in both directions to each of arms 12 and 13. The inlet may be separated as shown or it may comprise a single inlet feeding in both directions. Scroll 10 is used to feed a tip turbine fan generally indicated at 14 and having tip turbine buckets 15 and fan blades 16 in the well-known manner.

In order to drive the tip turbine fan which, in the installation being described, is disposed closely adjacent the scroll in a parallel horizontal plane below or down stream of the scroll for vertical lift, the scroll is provided with airfoil shaped nozzle blades 17 which are aligned with turbine blades 15 to direct exhaust gases onto turbine blades 15 and thus drive fan 16. As shown, it will be apparent that the fan is driven about an admission are of approximately in FIGURE 1.

When the remote gas generator or engine is replaced or exhaust gas is bled off for other purposes, the operating characteristics are changed and the turbine nozzle area defined by blades 17 also should be changed for eflicient operation. In other words, the desired turbine nozzle area defined by blades 17 varies with these other varying characteristics. Consequently, it is necessary to provide some means for adjusting the nozzle area without adverse effects on any of the operating structure.

each vane.

The present invention proposes to do this by blocking off the ends of the scroll arms 12 and 13 by providing cambered vanes 18 between nozzle blades 17 as shown in FIGURES 2 and 3. These vanes are disposed between adjacent blades by using a selected number of vanes as required at the end sectors of the sCIOll arms and progressing toward the inlet to block off discrete sectors of the scroll. The reason for this is that, in effect, the exhaust gas entering the scroll then sees only a shorter scroll sector depending on the selected blockage of the ends of the arms. Consequently, there is no high loss blockage to create undersirable pressure loss. Instead, the arrangement merely cuts down on the length of the flow passage by locating the vanes at the end sectors of the scroll arms.

In order to provide the required area for varying conditions, the individual vanes are adjustable to rotate into a closed position as shown in FIGURE 3 or can operate in the open position as shown dotted in FIG- URE 3. It will be apparent that the camber of the blades is important in the non-blocked position to reduce the resistance to the normal flow of gases and reduce losses.

In order to simplify the operating linkage and because of the close proximity of the turbine fan 14 it is not necessary to pivot vanes 18 outside of the vane envelope and thus no translation of vanes 18 takes place. Rotation is obtained preferably by providing a pivot 19 Within the vanes to rotate about a longitudinal axis through With this pivot arrangement it can be seen that the whole vane mechanism is operable completely within the envelope of nozzle blades 17, and in no position of operation do vanes 18 extend beyond the envelope of blades 17. The vanes 18 are normally operable in the open or closed position but obviously may be operable in intermediate positions also.

In order to operate the vanes, relatively simple mechanism is provided as shown in FIGURE 4. In this figure it can be seen that vane 18 is simply supported in two bearings 20 and 2 1 in which pivot 19 rotates. The above bearings are clearly out of the hot gas flow of the exhaust gases in arm- 12 as directed by nozzle blades 17 to turbine buckets 15. Pivot 19 may extend beyond bearing 21 where mechanism is provided to rotate vane 18. This mechanism may consist of a simple bracket 22 fixedly secured to the scroll arm 12. Link 23 is attached to pivot shaft 19 and secured to the bracket 22 by a bolt-nut 24. As shown in FIGURE 5, bracket 22 may be wide enough to have several openings 25 through which bolt-nut 24 may be placed to rotate link 23- into the position shown. Thus, installation in the wing of an aircraft merely requires an access door over the linkage in order to reach in with a Wrench and adjust vanes 18 to any position desired. Such linkage is removed from the hot gas flow, it is very lightweight and simplitied. As just described, each vane 18 is independently adjustable by similar linkage.

Under some circumstances, it may be desirable to operate the vanes by remote control, and, if desired, this may be accomplished by means of a link 26, shown in FIGURE 6, tieing all the links 23 together and link 26 may be actuated by any suitable actuator under a remote control not shown. For the most part, the linkage shown in FIG. is satisfactory since generally the trim vanes 18 will be set in one position and locked for a given operating condition or gas generator.

From the above description, it will be seen that the location of the vanes at the ends of the scroll arms reduces the admission are thus providing a shorter gas path but no blockage to the gas ilow and hence no resultant losses. Further, the simple operating mechanism is all disposed completely within the maximum envelope of the fan as shown in FIGURE 1 and even within the envelope of the nozzle blades as shown in FIGURE 3.

Thus, no additional space is required and no translation of the vanes is required. The decrease in the nozzle efiiciency between the blades 17 is extremely low by virtue of the individual adjustment available and the cambered vanes '18. Further, the operating mechanism is reduced to a minimum and disposed outside of the hot gas flow where it is easily accessible for adjustment either permanent or temporary.

While there have been described preferred forms of the invention, obviously modifications and variations are possible inlight of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

I claim:

1. In a tip turbine fan installation having,

a scroll of general U-shape,

gas inlet means in the bight of the U to direct gas to each arm thereof,

a tip turbine fan disposed adjacent the scroll,

said fan and said scroll being in substantially parallel relationship,

a plurality of nozzle blade means in and coextensive with said scroll aligned with the tip turbine for directing gases thereto to drive said fan,

nozzle area trim means comprising,

vanes disposed between a selected number of said blades,

pivot means passing through said vanes for rotation about an axis through the vanes to vary and block the area between said selected number of blades,

said vanes being located only in the arms of the U- shaped scroll and being operable to block or vary only those sectors of each of said scroll arms which extend from the end of the arm a short distance toward said inlet.

2. Apparatus as described in claim 1 having link means connected to said vanes for adjustment thereof.

3. Apparatus as described in claim 1 wherein the scroll and fan are in substantially parallel horizontal planes for vertical lift on the installation.

4. In a tip turbine fan installation having,

a scroll of generally U-shape,-

exhaust gas inlet means in the bight of the U to direct gas to each arm thereof,

a tip turbine fan disposed adjacent and downstream of the scroll in a plane substantially parallel thereto,

nozzle blades in and coextensive with said scroll aligned with said tip turbine for directing exhaust gases about an admission are defined by the scroll to drive said fan,

nozzle area trim means operable completely within the scroll comprising,

cambered vanes disposed only between a selected number of blades in end sectors of each of the arms of said scroll,

pivot means in each vane for rotation about a longitudinal axis through the vanes to vary and block the area between said selected number of blades,

whereby said vanes may be operated to reduce the admission are of said scroll without disrupting the uniform flow of gas through the bight.

5. Apparatus as described in claim 4 having a link means econnected to said vanes for adjustment thereof.

6. Apparatus as described in claim 4 wherein the scroll and fan are in substantially parallel horizontal planes for vertical lift on the installation.

References Cited by the Examiner UNITED STATES PATENTS 294,929 3/ 1884 Stubbs 253-122 429,780 6/1890 Shelton 253122 2,518,600 8/1950 Browne 230122 (Other references on following page) 5 UNITED STATES PATENTS Bloomberg 253-78 T-rumpler 230-114 Paetz 138-46 Balje et a1. 253-55 5 Lane 244-12 Rowe 244-12 Rowe 253-78 Rowe et a1. 253-78 6 FOREIGN PATENTS 10,917 3/ 1880 Germany. 277,779 10/ 1927 Great Britain. 880,606 10/ 1961 Great Britain.

MARK NEWMAN, Primary Examiner.

LAURENCE V. EFNER, JULIUS E. WEST, Examiners.

I. GEN DELMAN, W. E. BURNS, Assistant Examiners. 

1. IN A TIP TURBINE FAN INSTALLATION HAVING, A SCROLL OF GENERAL U-SHAPE, GAS INLET MEANS IN THE BIGHT OF THE U TO DIRECT GAS TO EACH ARM THEREOF, A TIP TURBINE FAN DISPOSED ADJACENT THE SCROLL, SAID FAN AND SAID SCROLL BEING IN SUBSTANTIALLY PARALLEL RELATIONSHIP, A PLURALITY OF NOZZLE BLADE MEANS IN AND COEXTENSIVE WITH SAID SCROLL ALIGNED WITH THE TIP TURBINE FOR DIRECTING GASES THERETO TO DRIVE SAID FAN, NOZZLE AREA TRIM MEANS COMPRISING, VANES DISPOSED BETWEEN A SELECTED NUMBER OF SAID BLADES, PIVOT MEANS PASSING THROUGH SAID VANES FOR ROTATION ABOUT AN AXIS THROUGH THE VANES TO VARY AND BLOCK THE AREA BETWEEN SAID SELECTED NUMBER OF BLADES, SAID VANES BEING LOCATED ONLY IN THE ARMS OF THE USHAPED SCROLL AND BEING OPERABLE TO BLOCK OR VARY ONLY THOSE SECTORS OF EACH OF SAID SCROLL ARMS WHICH EXTEND FROM THE END OF THE ARM A SHORT DISTANCE TOWARD SAID INLET. 